Constrained somatostatin agonists and antagonists

ABSTRACT

The present invention relates to a compound of general formula I ##STR1## for treating medical disorders related to binding to human somatostatin receptor subtypes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. 119 of Danishapplication serial no. 1216/96 filed Oct. 31, 1996, the contents ofwhich are fully incorporated herein by reference.

FIELD OF INVENTION

The present invention relates to compounds, pharmaceutical compositionscontaining them, methods of treatment and their use for preparingpharmaceutical compositions for treating medical disorders related tobinding to human somatostatin receptor subtypes.

BACKGROUND OF THE INVENTION

Somatostatin (somatotropin release inhibiting factor; SRIF), atetradecapeptide originally isolated from ovine hypothalamus on thebasis of its ability to inhibit growth hormone release from anteriorpituitary cells (Brazeau, P. et al., Science 179, 77-79, 1973) has beenshown to be present in several other tissues (for a review see Reichlin,S., N. Engl. J. Med. 309, 1495-1501, 1983 and ibid, 1556-1563).Somatostatin appears to have widespread functions as a modulator ofneuronal activity as well as of endocrine and exocrine secretion.Inhibitory effects of this peptide on the release of a variety ofhormones such as growth hormone, prolactin, glucagon, insulin, gastrinand thyroid stimulating hormones have been described (for a review seeWass, J. A. H., in Endocrinology, ed. deGrott, L. J., vol 1, 152-166,1989). Somatostatin is best regarded as belonging to a phylogeneticallyancient, multigene family of peptides with two important bioactiveproducts, namely SRIF-14 (SRIF) and SRIF-28, a congener of SRIF extendedat the N-terminus.

The regulatory functions of SRIF are mediated by specific membranereceptors. Currently, only agonists are available to study thepharmacology of SRIF receptors. High-affinity saturable binding siteshave been demonstrated in a number of tissues, e.g. pituitary gland,brain and pancreas. Within the last few years the cloning and isolationof five somatostatin receptor genes has been reported for variousspecies (human, rat, mouse and bovine). Structural analysis of theencoded proteins revealed that the somatostatin receptor proteins(SST1-SST5) represent a distinct receptor subfamily (named the A5subfamily) belonging to the superfamily of G protein-coupled receptorswith seven putative membrane spanning regions.

Recent work on the development of nonpeptide structures substituting thepeptide backbone of small cyclic peptides with a β-D-glucose scaffold(Hirschmann, R. et al., J.Am. Chem.Soc. 115, 12550-12568, 1993) orxylofuranose scaffold (Papageorgiou, C. et al., Bioorg.Med.Chem.Lett. 2,135-140, 1992) demonstrated low somatostatin receptor affinity. However,these structures are nonselective displaying higher affinities for bothβ2-adrenergic receptors and tachykinin receptors. Thus, there have beenno reports in the literature on the successful development of aselective, competitive somatostatin receptor ligand of nonpeptideorigin.

The H3 receptor is known and of current interest for the development ofnew medicaments (see. e.g. Stark, H.; Schlicker, E.; Schunack, W. DrugsFut. 1996, 21, 507-520; Leurs, R.; Timmerman, H.; Vollinga, R. C.Progress in Drug Research 1995, 45, 107-165). The histamine H3 receptoris a presynaptic autoreceptor located in both the central and theperipheral nervous system, the skin and in organs such as the lung, theintestine, probably the spleen and the gastrointestinal tract.Stimulation of the H3 receptor with an agonist leads to an inhibition ofthe biosynthesis and the release of histamine (autoreceptor), and alsoof other neurotransmitters (heteroreceptor), such as serotonine andacetylcholine. These findings indicate that the H3 receptor is a targetfor new therapeutics.

SUMMARY OF THE INVENTION

Accordingly, the present invention relates to a compound of generalformula I ##STR2## wherein A is aryl, optionally substituted with one ormore halogens, amino groups, hydroxyl groups, nitro groups, C₁₋₆ -alkylgroups, C₁₋₆ -alkoxy groups or aryl groups,

B is aryl, optionally substituted with one or more halogens, aminogroups, hydroxyl groups, C₁₋₆ -alkyl groups, C₁₋₆ -alkoxy groups or arylgroups,

m is 0, 1, 2, 3, 4, 5 or 6,

n is 0, 1, 2 or 3,

Y is a valence bond or a group having the formula ##STR3## wherein q ands each independently are 0, 1, 2, 3, 4 or 5, and

q+s is 1, 2, 3, 4or 5,

R¹ is hydrogen or C₁₋₆ -alkyl optionally substituted with halogen,amino, hydroxy, alkoxy or aryl;

X is ═S, ═O or ═NR³, wherein R³ is hydrogen, --C(O)Ph, or --CN,

E is a group having the formula ##STR4## wherein p is 0, 1, 2, 3 or 4,

r is 1, 2, 3, 4, 5or 6,

Z is --N< or --CH<,

D is aryl, optionally substituted with one or more halogens, aminogroups, hydroxyl groups, C₁₋₆ -alkyl groups, C₁₋₆ -alkoxy groups,piperidinyl groups or aryl groups;

R² is hydrogen or C₁₋₆ -alkyl optionally substituted with halogen,amino, hydroxy, alkoxy or aryl,

with the proviso that if m=0 then Y is not a valence bond;

and the pharmaceutically acceptable salts thereof.

The compounds of formula I comprise any optical isomers thereof, in theform of separated, pure or partially purified optical isomers or racemicmixtures thereof.

DETAILED DESCRIPTION OF THE INVENTION

In the above structural formulas and throughout the presentspecification, the following terms have the indicated meanings:

The C₁₋₆ -alkyl groups specified above are intended to include thosealkyl groups of the designated length in either a linear or branched orcyclic configuration. Examples of linear alkyl are methyl, ethyl,propyl, butyl, pentyl, and hexyl. Examples of branched alkyl areisopropyl, sec-butyl, tert-butyl, isopentyl, and isohexyl. Examples ofcyclic alkyl are C₃₋₆ -cycloalkyl such as cyclopropyl, cyclobutyl,cyclopentyl and cyclohexyl.

The alkoxy groups, preferably C₁₋₆ -alkoxy groups specified above areintended to include those alkoxy groups of the designated length ineither a linear or branched or cyclic configuration. Examples of linearalkoxy are methoxy, ethoxy, propoxy, butoxy, pentoxy, and hexoxy.Examples of branched alkoxy are isopropoxy, sec-butoxy, tert-butoxy,isopentoxy, and isohexoxy. Examples of cyclic alkoxy are C₃₋₆-cycloalkoxy such as cyclopropyloxy, cyclobutyloxy, cyclopentyloxy andcyclohexyloxy.

In the present context, the term "aryl" is intended to include aromaticrings, such as carbocyclic and heterocyclic aromatic rings selected fromthe group consisting of phenyl, naphthyl, thienyl, furyl, furanyl,pyridinyl, pyridyl, 1-H-tetrazol-5-yl, thiazolyl, imidazolyl,isoquinolinyl, indolyl, isoindolyl, piperazinyl, pyridazinyl,pyrimidinyl, thiadiazolyl, pyrazolyl, oxadiazol, oxazolyl, isoxazolyl,thiophenyl, quinolinyl, pyrazinyl, triazinyl, triazolyl, tetrazolyl,isoindazolyl, benzotriazolyl or isothiazolyl, optionally substituted byone or more halogen, amino, hydroxy, carboxylic acid, carboxylic amide,nitrile, aldehyde, nitro, trihalogenomethyl, C₁₋₆ -alkylketone, C₁₋₆-alkyl, C₁₋₆ -alkoxy or aryl.

The term "C₁₋₆ -alkylketone" is intended to include the above C₁₋₆-alkyl groups connected to a ketone group.

The term "halogen" is intended to include Cl, F, Br and I.

The term "treatment" is intended to comprise treatment of a patient,such as a mammal, e.g. a human, having a disease as well as profylactictreatment of said patient in order to inhibit or control the disease.

In a preferred embodiment of the above compound of formula I R¹ and R²are each independently hydrogen or C₁₋₆ -alkyl, such as hydrogen.

In another preferred embodiment of the above compound of formula I(CH₂)_(r) is a C₁₋₆ alkylene, such as methylene, ethylene, propylene,butylene, pentylene and hexylene, e.g. methylene, ethylene or propylene,such as ethylene.

In a further preferred embodiment of the above compound of formula I Yis a valence bond or q and s are each independently 0, 1, 2, 3 or 4 andq+s is 3 or 4.

In a still further preferred embodiment of the above compound of formulaI X is ═S, ═NH or ═NC(O)Ph. In a particular embodiment X is ═S.

In a further preferred embodiment of the above compound of formula I Ais phenyl or pyridinyl, optionally substituted with one or two halogens,amino groups, hydroxyl groups, nitro groups, C₁₋₆ -alkyl groups, C₁₋₆-alkoxy groups or aryl groups, such as pyridinyl optionally substitutedwith one halogen, such as bromine.

In a still further preferred embodiment of the above compound of formulaI B is phenyl or pyridinyl, optionally substituted with one or twohalogens, amino groups, hydroxyl groups, C₁₋₆ -alkyl groups, C₁₋₆-alkoxy groups or aryl groups, such as phenyl optionally substitutedwith one or two halogens, such as chlorine and/or bromine.

In a further preferred embodiment of the above compound of formula I Dis phenyl, benzotriazolyl, imidazolyl or pyridinyl, optionallysubstituted with one or two halogens, amino groups, hydroxyl groups,C₁₋₆ -alkyl groups, C₁₋₆ -alkoxy groups, piperidinyl groups or arylgroups, such as optionally substituted with one piperidinyl orimidazolyl. In a particular embodiment D is phenyl substituted with animidazolyl group or is imidazolyl, optionally substituted with one ortwo halogens, amino groups, hydroxyl groups, C₁₋₆ -alkyl groups, C₁₋₆-alkoxy groups, piperidinyl groups or aryl groups.

In a still further preferred embodiment of the above compound of formulaI m is 0, 1, 2, 3 or 4, such as 2, 3 or 4.

In a further preferred embodiment of the above compound of formula I nis 0, 1 or 2, such as

In a still further preferred embodiment of the above compound of formulaI p is 0, 1 or 2, such as 0 or 2.

In a further preferred embodiment of the above compound of formula I ris 1, 2 or 3, such as 2.

In a still further preferred embodiment of the above compound of formulaI q+s is 2, 3 or 4, such as 3 or 4.

Whenever a heteroaryl or aryl is substituted such substitution(s) may bein any possible ring position, which may be recognized by the skilledperson without any undue burden.

In a broader aspect the invention relates to somatostatin receptorligands of nonpeptide origin, including the compounds of formula 1,which have affinity to the somatostatin receptor proteins selected fromSST1, SST2, SST3, SST4 and SST5.

In an embodiment of the somatostatin receptor ligands of nonpeptideorigin, said ligands have selective affinity to one or two of thesomatostatin receptor proteins selected from SST1, SST2, SST3, SST4 andSST5.

In a further embodiment of the somatostatin receptor ligands ofnonpeptide origin, said ligands have selective affinity to SST1.

In a still further embodiment of the somatostatin receptor ligands ofnonpeptide origin, said ligands have selective affinity to SST2.

In a further embodiment of the somatostatin receptor ligands ofnonpeptide origin, said ligands have selective affinity to SST3.

In a still further embodiment of the somatostatin receptor ligands ofnonpeptide origin, said ligands have selective affinity to SST4.

In a further embodiment of the somatostatin receptor ligands ofnonpeptide origin, said ligands have selective affinity to SST5.

In a still further embodiment of the somatostatin receptor ligands ofnonpeptide origin, said ligands have selective affinity to SST1 andSST2, SST2 and SST3, SST3 and SST4, SST4 and SST5, SST1 and SST3, SST2and SST4 or SST3 and SST5.

Preferred compounds of the present invention are

1-(2-((5-Bromopyridin-2-yl)-(3,4-dichlorobenzyl)amino)ethyl)-3-(4-piperidine-1-ylphenyl)thiourea##STR5##1-(3H-Benzotriazol-5-yl)-3-(2-((5-bromopyridin-2-yl)-(3,4-dichlorobenzyl)amino)ethyl)thiourea##STR6## 4-(1H-Imidazol-4-yl)piperidine-1-carbothioic acid(2-((5-bromopyridine-2-yl)-(3,4-dichlorobenzyl)amino)ethyl)amide##STR7##1-(2-((5-Bromopyridin-2-yl)-(3,4-dichlorobenzyl)amino)propyl)-3-(4-piperidine-1-ylphenyl)thiourea##STR8##1-(2-((5-Bromopyridin-2-yl)-(3,4-dichlorobenzyl)amino)butyl)-3-(3-(1H-imidazol-4-yl)phenyl)thiourea##STR9## N¹-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)propyl)-4-(pyridine-2-yl)piperazine-1-carboxamidine##STR10##1-(3-(((5-Bromopyridin-2-yl)-(3,4-dichlorobenzy)amino)methyl)cyclohexyl)-3-(3-(1H-imidazol-4-yl)phenyl)thiourea##STR11## N¹-(3-(N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino)cyclopentyl)-4-(pyridin-2-yl)piperazine-1-carboxamidine##STR12##

The compounds of the invention can be employed to mediate the biologicaleffects of somatostatin agonists or antagonists. It is believed thatcompounds of formula I exhibit an improved bioavailability because theycontain no amide bonds susceptible to cleavage by proteolytic enzymes.The increased resistance to proteolytic degradation combined with thereduced size of the compounds of the invention in comparison with knownsomatostatin agonists and antagonists is expected to possess beneficialproperties such as increased peroral absorption, increased biologicalhalf-life, lack of immunogenicity, and the ability to cross theblood-brain barrier compared to that of the compounds suggested in theprior literature.

Compounds of formula I are believed to be useful for the development ofpharmaceutical, therapeutic, and diagnostic techniques. Accordingly, theinvention also provides methods for producing a prophylactic ortherapeutic response in a mammal by administering to the mammal apharmaceutically effective amount of one or more compounds of theinvention. In accordance with preferred embodiments, the presentinvention provides methods for producing such responses by modulatingthe activity of mammalian somatostatin receptors by administering aneffective amount of one or more compounds of the invention.

In another aspect of the present invention the compounds of formula Iwherein D is phenyl substituted with imidazolyl or is imidazolyl,optionally substituted with one or more halogens, amino groups, hydroxylgroups, C₁₋₆ -alkyl groups, C₁₋₆ -alkoxy groups, piperidinyl groups oraryl groups, interact with the H3 receptor and may thus be used for thetreatment of airway disorders such as asthma, as anti-diarrhoeals andfor the modulation of gastric acid secretion. The compounds of thepresent invention may also be used for the treatment of diseasesassociated with the regulation of sleep and wakefulness and for thetreatment of narcolepsy and attention deficite disorders. Moreover thesenew compounds may be used as non-amphetamine-like stimulants or assedatives. Further, the compounds of the invention may be used for thetreatment of eating disorders (e.g. anorexia or bulimia) by virtue oftheir appetite regulating properties. Thus, these compounds may beuseful for the prevention of diseases related to obesity, such asdiabetes and cardiovascular disorders. The present compounds could alsobe used for treatment of conditions associated with epilepsy.Additionally these compounds can be used for the treatment of motionsickness and vertigo. Further, the compounds of the present inventionmay be used for the treatment of dementia and Alzheimer disease.

The compounds of the present invention may have one or more asymmetriccenters and stereoisomers in the form of separated, pure or partiallypurified stereoisomers or racemic mixtures thereof are intended to beincluded in the scope of the invention.

General Methods

General Method A ##STR13##

Compounds of formula I may be prepared as shown in reaction scheme Istarting with an arylhalogenide 1 which may be reacted with adiaminoalkyl 2 in an appropriate solvent such as pyridine and undernitrogen at reflux for an appropriate time. The excess diaminoalkyl andsolvent may be removed in vacuo and an apolar solvent such astetrahydrofuran may be added to precipitate the diaminoalkyl salt. Theintermediate 3 may be obtained by distillation or chromatography bymethods known in the art.

The intermediate 3 may be alkylated with an arylalkylhalogenide 4 aftertreatment with a base such as sodium hydride under conditions known inthe art to give a 1,1-disubstituted primary or secondary amine 5. Then 5in a solvent like tetrahydrofuran or ethanol may be reacted with anisothiocyanate (or isocyanate) 6, prepared as shown in scheme 2 or bymethods known for those skilled in the art, stirred overnight andconcentrated in vacuo to afford a crude product 7. The isothiocyanate(or isocyanate) may be protected and deprotected according to methodsdescribed in the art (e.g. T. W. Greene, Protective Groups in OrganicSynthesis, 2nd. edition, John Wiley and Sons, New York, 1991). The crudeproduct 7 may be purified by methods known for those skilled in the artsuch as chromatography, to yield the final product 7 which is a compoundof the general formula I. ##STR14##

The isothiocyanate 6 as described in scheme I may be prepared from theappropriate protected primary amine 8 in a solvent like tetrahydrofuranand carbondisulfide in the presence of a reagent such asdicyclohexylcarbodiimide or other coupling reagents known in theliterature under chilled conditions. The mixture may be stirredovernight and the solvent removed and the residue may be triturated withether to remove dicyclohexylthiourea. The remaining product may bedistilled under vacuum or chromatographed using technics known to thoseskilled in the art, to yield the isothiocyanate 6.

The corresponding isocyanate 6b may be prepared from a protected primaryamine 8 and carbonyidiimidazole in an appropriate solvent followingprocedures known for those skilled in the art. ##STR15## General MethodB ##STR16##

Compounds of formula I may be prepared as shown in reaction scheme IIIstarting with an appropriate amine 5, prepared as described in reactionscheme I, and an activated imine 8 in which R³ may be benzoyl(--COPh) ornitrile (--CN) and R⁴ may be thiomethoxy (--SCH₃), phenoxy (--OPh) orchloride (--Cl) in an appropriate solvent such as dimethylformamide ortetrahydrofuran at an appropriate temperature for an appropriate time togive the intermediate 9. The intermediate 9 may further react with anamine 2 in an appropriate solvent such as pyridine with or without acatalyst e.g. silver salts (e.g. AgNO₃) at an appropriate temperaturefor an appropriate time to form the product 10 which is a compound ofthe general formula I.

When the compound 10 (in which R³ is an activating group such as benzoylor nitrile) is treated with 1.5 M aqueous hydrogen chloride for anappropriate time at an appropriate temperature the compound 10 (in whichR³ is hydrogen) may be formed which is a compound of the general formulaI.

The intermediates in reaction scheme III may be protected anddeprotected according to methods described in the art (e.g. T. W.Greene, Protective Groups in Organic Synthesis, 2nd. edition, John Wileyand Sons, New York, 1991).

The guanidine derivatives and their salts thus obtained can be isolatedand purified by methods which are known by those skilled in the art.

General Method C ##STR17##

Compounds of formula I may be prepared as shown in reaction scheme Istarting with an arylhalogenide 11 which may be reacted with adiaminoalkyl 12 in an appropriate solvent such as pyridine and undernitrogen at reflux for an appropriate time. The excess diaminoalkyl andsolvent may be removed in vacuo and an apolar solvent such astetrahydrofuran may be added to precipitate the diaminoalkyl salt. Theintermediate 13 may be obtained by distillation or chromatography bymethods known in the art.

The intermediate 13 may be alkylated with an arylalkylhalogenide 14after treatment with a base such as sodium hydride under conditionsknown in the art to give a 1,1-disubstituted primary amine 15.

The isothiocyanate (X═S) or isocyanate (X═O) 16 may be obtained bymethods as described in scheme II or by methods known for those skilledin the art.

Then 16 in a solvent like tetrahydrofuran or ethanol may be reacted withan amine 17, stirred overnight and concentrated in vacuo to the thioureaor urea 18. The thiourea or urea may be protected and deprotectedaccording to methods described in the art (e.g. T. W. Greene, ProtectiveGroups in Organic Synthesis, 2nd. edition, John Wiley and Sons, NewYork, 1991). The crude product 18 may be purified by methods known forthose skilled in the art such as chromatography, to yield the finalproduct which is a compound of the general formula I.

Pharmacology

Compounds of the invention are preferred to the extent that theyselectively and effectively are bound by somatostatin receptor subtypespermanently expressed in eukaryotic cell lines. It will be recognizedthat the degree to which a compound is bound by a receptor is known asits binding affinity. The affinity of a compound is commonly expressedas the inhibitory concentration at which the compound is able todisplace 50% of another compound already bound to the receptor (IC₅₀).In the case of ligand-binding studies at somatostatin receptors, thecompound that is displaced is a radioactive agonist, e.g. ¹²⁵ I-Tyr¹¹-SRIF-14, at the receptor. It is preferred in accordance with thepresent invention that a compound possess a clinically effective IC₅₀ inat least one mammal; that is, it should possess an IC₅₀ which is lowenough to inhibit binding of radiolabelled agonist to somatostatinreceptors while causing a minimum of unacceptable side effects in themammal. As will be recognized, clinically effective concentrations varydepending on a number of factors, such as the pharmacokineticcharacteristics and stability of the compound under study and thus mustbe determined empirically for each compound and each factor. In general,it is desired that the potency of a compound of the invention be asgreat as possible, preferable greater than or equal to the nativesomatostatin. Compounds displacing radiolabelled agonist at somatostatinreceptors could belong to one of two classes, either agonists orantagonists. Simple ligand-binding studies will not distinguish betweenthese two classes. All five somatostatin receptor subtypes have beenshown to inhibit the activity of adenylyl cyclase via the G proteinsubunit G_(i) (Patel, Y. C. et al. Biochem. Biophys.Res.Commun.,198:605-612, 1994). By direct activation of adenylyl cyclase byforskolin the inhibitory action of somatostatin agonists could beemployed. Compounds specifically reversing the inhibitory action of SRIFon cyclic AMP accumulation will be termed somatostatin receptorantagonists.

Those skilled in the art will appreciate that a wide variety ofprophylactic, diagnostic, and therapeutic treatments may be preparedfrom the compounds and compositions of this invention, due to agonism orantagonism at somatostatin receptors. For example, by administering aneffective amount of compound, prophylactic or therapeutic responses canbe produced in a human or some other type mammal. Preferred responsesare modulation of glucagon and insulin secretion to treat type I andtype II diabetes; inhibition of cell proliferation and growth to treatvarious endocrine and exocrine tumors; modulation of growth hormonesecretion to treat dwarfism, acromegaly, and other growth abnormalities;modulation of immune responses to treat autoimmune diseases, rheumatoidarthritis, and other inflammations; modulation of neuronal activity totreat diseases related to the central nervous system, i.e. pain,anxiety, memory disorders, affective disorders, and Alzheimer's disease;modulation of intestinal water uptake to treat congestion and diarrhea;inhibition of arterial smooth muscle cell proliferation to treatrestenosis and arteriosclerosis; inhibition of airway mucous secretionto treat asthma and mucoviscidosis; modulation of lipid metabolism andregulation of energy balance to treat obesity; inhibition of acidsecretion to treat ulcer; inhibition of pancreatic secretions to treatacute pancreatitis; and treatment of chronic fatigue syndrom (CFS). Itwill be appreciated that the production of prophylactic or therapeuticresponses includes the initiation or enhancement of desirable responses,as well as the cessation or suppression of undesirable responses. When,in particular a compound of the invention, or a pharmaceuticallyacceptable salt thereof, has high and/or selective affinity to thesomatostatin receptor protein designated SSTR4, such compound may beuseful for the treatment of a disease associated with an adversecondition in the retina and/or iris-ciliary body of a mammal. Suchconditions being high intraocular pressure (IOP) and/or deep ocularinfections. The diseases which may be treated are e.g. glaucoma, stromalkeratitis, iritis, retinitis, cataract and conjunctivitis.

As can be seen, the present invention provides a variety of compoundswhich effectively and selectively are bound to somatostatin receptors.The compounds are capable of forming pharmaceutically acceptable saltswith various inorganic and organic acids, and such salts are also withinthe scope of this invention. Examples of such salts are acid additionsalts including acetate, adipate, benzoate, benzenesulfonate, bisulfate,butyrate, citrate, camphorate, camphorsulfonate, ethanesulfonate,fumarate, hemisulfate, heptanoate, hexanoate, hydrochloride,hydrobromide, hydroiodide, lactate, maleate, methanesulfonate,2-naphthalenesulfonate, nitrate, oxalate, pamoate, persulfate, picrate,pivalate, propionate, succinate, sulfate, tartrate, tosylate, andundecanoate. The salts may be formed by conventional means, such as byreacting the free base form of the product with one or more equivalentsof the appropriate acid in a solvent or medium in which the salt isinsoluble, or in a solvent such as water, which is later removed invacuo or by freeze drying. The salts also may be formed by exchangingthe anions of an existing salt for another anion on a suitable ionexchange resin.

In another aspect, the present invention relates to a pharmaceuticalcomposition comprising, as an active ingredient, a compound of thegeneral formula I or a pharmaceutically acceptable salt thereof togetherwith a pharmaceutically acceptable carrier or diluent. Pharmaceuticalcompositions containing a compound of the present invention may beprepared by conventional techniques, e.g. as described in Remington'sPharmaceutical Sciences, 1985. The compositions may appear inconventional forms, for example capsules, tablets, aerosols, solutions,suspensions or topical applications.

The pharmaceutical carrier or diluent employed may be a conventionalsolid or liquid carrier. Examples of solid carriers are lactose, terraalba, sucrose, cyclodextrin, talc, gelatin, agar, pectin, acacia,magnesium stearate, stearic acid or lower alkyl ethers of cellulose.Examples of liquid carriers are syrup, peanut oil, olive oil,phospholipids, fatty acids, fatty acid amines, polyoxyethylene or water.

Similarly, the carrier or diluent may include any sustained releasematerial known in the art, such as glyceryl monostearate or glyceryldistearate, alone or mixed with a wax.

If a solid carrier is used for oral administration, the preparation maybe tabletted, placed in a hard gelatin capsule in powder or pellet formor it can be in the form of a troche or lozenge. The amount of solidcarrier will vary widely but will usually be from about 25 mg to about 1g. If a liquid carrier is used, the preparation may be in the form of asyrup, emulsion, soft gelatin capsule or sterile injectable liquid suchas an aqueous or non-aqueous liquid suspension or solution.

A typical tablet which may be prepared by conventional tablettingtechniques may contain:

    ______________________________________                                        Core:                                                                         ______________________________________                                        Active compound (as free compound or salt thereof)                                                       100    mg                                          Colloidal silicon dioxide (Aerosil)                                                                      1.5    mg                                          Cellulose, microcryst. (Avicel)                                                                          70     mg                                          Modified cellulose gum (Ac-Di-Sol)                                                                       7.5    mg                                          Magnesium stearate                                                            Coating:                                                                      HPMC approx.               9      mg                                          *Mywacett 9-40 T approx.   0.9    mg                                          ______________________________________                                         *Acylated monoglyceride used as plasticizer or film coating.             

For nasal administration, the preparation may contain a compound offormula I dissolved or suspended in a liquid carrier, in particular anaqueous carrier, for aerosol application. The carrier may containadditives such as solubilizing agents, e.g. propylene glycol,surfactants, absorption enhancers such as lecithin (phosphatidylcholine)or cyclodextrin, or preservatives such as parabenes.

Generally, the compounds of the present invention are dispensed in unitdosage form comprising 50-200 mg of active ingredient together with apharmaceutically acceptable carrier per unit dosage.

The dosage of the compounds according to this invention is suitably1-500 mg/day, e.g. about 100 mg per dose, when administered to patients,e.g. humans, as a drug.

It has been demonstrated that compounds of the general formula I possessthe ability to bind to human somatostatin receptors. The compounds maytherefor be used in the treatment of conditions which require highsomatostatin receptor affinity.

Thus, in a particular aspect, the present invention relates to apharmaceutical composition for binding to somatostatin receptors, thecomposition comprising, as an active ingredient, a compound of thegeneral formula I or a pharmaceutically acceptable salt thereof togetherwith a pharmaceutically acceptable carrier or diluent.

In a further aspect, the present invention relates to a method ofbinding to somatostatin receptors, the method comprising administeringto a subject in need thereof an effective amount of a compound of thegeneral formula I or a pharmaceutically acceptable salt thereof.

In a still further aspect, the present invention relates to the use of acompound of the general formula I or a pharmaceutically acceptable saltthereof for the preparation of a medicament for binding to thesomatostatin receptors.

Those skilled in the art will appreciate that a wide variety ofprophylactic, diagnostic, and therapeutic treatments may be preparedfrom the synthetic compounds and compositions of the invention, due inlarge part to the competition--that is, agonism or antagonism--of thesemoieties with the naturally occurring SRIF or SRIF-28. For example, byadministering an effective amount of a compound of the invention,prophylactic or therapeutic responses can be produced in a human or someother type mammal. Preferred responses are produced by modulating--thatis, increasing, decreasing or otherwise modifying--the activity of atleast one somatostatin receptor subtype (i.e. SSTR1, SSTR2, SSTR3, SSTR4and SSTR5). It will be appreciated that the production of prophylacticor therapeutic responses includes the initiation or enhancement ofdesirable responses, as well as the cessation or suppression ofundesirable responses.

The compounds of formula I may be administered in pharmaceuticallyacceptable acid addition salt form or, where appropriate, as a alkalimetal or alkaline earth metal or lower alkylammonium salt. Such saltforms are believed to exhibit approximately the same order of activityas the free base forms.

Optionally, the pharmaceutical composition of the invention may comprisea compound of formula I combined with one or more compounds exhibiting adifferent activity, e.g., an antibiotic or other pharmacologicallyactive material.

The route of administration may be any route which effectivelytransports the active compound to the appropriate or desired site ofaction, such as oral, nasal, buccal, pulmonal, transdermal orparenteral, the oral route being preferred.

EXAMPLES

The process for preparing compounds of formula I and preparationscontaining them is further illustrated in the following examples, whichhowever, are not to be construed as limiting.

The structures of the compounds are confirmed by either elementalanalysis (MA) nuclear magnetic resonance (NMR) or mass spectrometry(MS). NMR shifts (δ) are given in parts per million (ppm) and onlyselected peaks are given. m.p. is melting point and is given in ° C. andis not corrected. Column chromatography was carried out using thetechnique described by W. C. Still at al, J. Org. Chem. 1978, 43,2923-2925 on Merck silica gel 60 (Art 9385). Compounds used as startingmaterials are either known compounds or compounds which can readily beprepared by methods known per se.

Abbreviations:

TLC: thin layer chromatography

DMSO: dimethylsulfoxide

min: minutes

h: hours

HPLC-Analysis:

Method A.

The RP-HPLC analysis was performed using UV detection at 254 nm and aLichrosorp RP-18 5 mM column, which was eluted at 1 ml/minute. Thecolumn was equilibrated with 20% acetonitrile in a buffer consisting of0.1M ammonium sulfate, which was adjusted to pH 2.5 with 4M sulfuricacid and eluted by a gradient of 20% to 80% acetonitrile in the samebuffer over 30 minutes. The gradient was then extended to 100%acetonitrile over 5 minutes followed by isocratic elution with 100%acetonitrile for 6 minutes.

Biological Assays

The affinity of somatostatin receptor ligands of nonpeptide originaccording to the invention (including the compounds covered by formulaI) to the somatostatin receptor proteins selected from SST1, SST2, SST3,SST4 and SST5, may be detected using the assays described below. Theskilled person will know which adjustments/modifications to make inorder to screen for specific ligands having affinity to one or more ofthe SST receptor subtypes 1-5. Moreover, in order to screen largecompound libraries to find the present ligands, conventional techniques(see e.g. Amersham™ SPA Technology) known to the skilled person may beused to modify the assays. One way of producing the present ligands isto provide a compound library of nonpeptide origin using conventionaltechniques (see e.g. Combinatorial chemistry in the discovery anddevelopment of drugs. Doyle, P. M., Journal Of Chemical Technology AndBiotechnology (1995) Vol. 64, 317-24) well-known to the skilled person,and screen for such ligands using the assays described below optionallywith modifications, thereby providing somatostatin receptor ligandsaccording to the invention.

Cell Lines Expressing SST Receptor Subtypes:

BHK cells (tk- ts13, ATCC CRL# 1632) and HEK 293 cells (ATCC CRL# 1573)were grown to 20-40% confluency in a tissue culture dish in DulbeccosModified Eagle Medium (DMEM) containing 1% penicillin/streptomycin, 10%foetal bovine serum, and 1% Glutamax™. Prior to transfection, the cellswere washed twice with calcium-free PBS after which 20 ml of serum-freeDMEM was added to the cells.

Transfection was carried out as described previously (productdescription: Lipofectamin, Gibco BRL cat. no. 18324-012). Briefly, 10 μgof cDNA encoding a SST receptor subtype inserted into the mammalianexpression vector pcDNA3 (Invitrogen) was diluted in 300 μl of sterilewater. 30 μg of Lipofectamin was diluted in 300 μl of sterile water. ThecDNA and Lipofectamin solutions were mixed and left at room temperaturefor 15 minutes. The Lipofectamin/cDNA mixture was added drop-wise to thecells (HEK 293 cells for SST₂, BHK for the other receptor subtypes)while gently swirling the plates. The cells were then incubated for16-24 hours, after which the medium was replaced with standard mediumcontaining 1 mg/ml Geneticin (G-418 sulfate). Resistant coloniesappearing after 1-2 weeks were isolated and propagated for furthercharacterization.

Binding Assay:

Cells expressing individual SST receptor subtypes were resuspended inbuffer (50 mM Tris-HCl (pH 7.4), 1 mM EGTA, 5 mM MgCl₂), andhomogenised. Membranes were washed twice in buffer by homogenisation andcentrifugation. Final membrane pellets were resuspended at a proteinconcentration of 125 μg/ml in buffer. Binding assays using 75 pM ¹²⁵I-Tyr¹¹ -SRIF (Amersham, IM-161) were done in duplicates in minisorbpolypropylene tubes in a volume of 250 μl. The assays were incubated at30-37° C. for 30-90 min depending on receptor subtype. Binding wasterminated by filtration through Whatman GF/B glass fiber filterspre-soaked for 4 hrs. in 0.5% polyethyleneimine and 0.1% BSA. Filterswere washed three times with 5 ml ice-cold 0.9% saline and counted in aPackard Cobra II Gamma Counter.

Functional Assay:

Cells expressing human SST receptors were seeded in 24-well tissueculture multidishes at 200,000 cells/well and grown for 16-20 hours. Themedium was removed, and fresh DMEM medium, supplemented with 1) 1 mM3-isobutyl-1-methylxanthine (IBMX), 2) 10 μM forskolin or medium, and 3)medium, SRIF, SST analogue, or compound was added. The plates wereincubated for 15-30 min at 37° C., the reaction medium removed and thecells lysed with 0.1 M sodium hydroxide. Following neutralisation with0.1 M hydrochloric acid an aliquot was removed for cAMP determinationusing Amersham SPA RIA (RPA 538).

EXAMPLE 1

4-(1H-Imidazol-4-yl)piperidine-1-carbothioic acid(2-((5-bromopyridine-2-yl)-(3,4-dichlorobenzyl)amino)ethyl)amide##STR18##

A mixture of 2,5-dibromopyridine (10.0 g, 42.2 mmol) and pyridine (4.24g, 53.6 mmol) in 1,2-diaminoethane (43 mL) was refluxed under nitrogenfor 18 h. The reaction mixture was evaporated under reduced pressure,cooled, and the resulting residue was treated with THF (150 mL) to yielda white precipitate. The precipitate was filtered and washed withadditional THF (100 mL). Evaporation of the filtrate afforded a brownoil which was vacuum distilled to give 6.48 g (71%)N-1-(5-bromopyrid-2-yl)ethane-1,2-diamine as a light yellow oil.

bp 134-142° C. (0.6 mm).

¹ H NMR (90 MHz CDCl₃) δ 1.33 (s, 2 H, NH₂), 2.92 (t, 2 H), 3.29 (m, 2H), 5.22 (br s, 1 H, NH), 6.31 (d, J=9 Hz, 1 H, pyridine H-3), 7.44 (dd,J=2.7 Hz, 9 Hz, 1 H, pyridine H-4), 8.09 (d, J=2.5 Hz, 1 H, pyridineH-6).

¹³ C NMR (90 MHz CDCl₃) δ 41.22, 44.74, 106.72, 108.67, 139.55, 148.54,148.70.

A 60% mineral oil dispersion of sodium hydride (0.584 g, 14.6 mmol) andN-1-(5-bromopyrid-2-yl)ethane-1,2-diamine (3.00 g, 13.9 mmol) in DMSO(30 mL) was stirred for 2 h under nitrogen. The suspension was cooled to0-5° C. and treated dropwise with 3,4-dichlorobenzyl chloride (2.71 g,13.9 mmol) in DMSO (15 mL). After stirring overnight at roomtemperature, the reaction mixture was poured into 200 mL of an ice-watermixture. The mixture was extracted with ethyl acetate (3×75 mL), and thecombined ethyl acetate extracts were washed with water (2×50 mL), dried(Na₂ SO₄), filtered, and evaporated to yield an oil. Flashchromatography on silica gel using CH₂ Cl₂ 90: CH₃ OH 5: Et₃ N 5 as thesolvent system gave 3.5 g ofN-1-(5-bromopyrid-2-yl)-1-(3,4-dichlorobenzyl)ethane-1,2-diamine as ayellow oil.

¹ H NMR (90 MHz CDCl₃) δ 1.45 (s, 2 H, NH₂), 2.92 (t, 2 H, NCH₂), 3.57(m, 2 H, CH₂ NH₂) 4.72 (s, 2 H, ArCH₂), 6.39 (d, J=9 Hz, 1 H, pyridineH-3), 7.32 (m, 4 H, ArH), 8.16 (d, J=2 Hz, 1 H, pyridine H-6).

¹³ C NMR (90 MHz CDCl₃) δ 39.82, 51.47, 51.95, 107.00, 107.27, 126.23,128.77, 130.62, 131.04, 132.73, 138.85, 139.77, 148.66, 156.62.

A mixture of dicyclohexylcarbodiimide (DCC) (2.74 g, 13.2 mmol) andcarbon disulfide (10.1 g, 132.6 mmol) in THF (30 mL) was cooled to -10°C. in an ice-salt bath and treated dropwise with a solution ofN-1-(5-bromopyrid-2-yl)-1-(3,4-dichlorobenzyl)ethane-1,2-diamine (5.00g, 13.2 mmol) in THF (20 mL). The reaction mixture was allowed to warmto room temperature and was stirred overnight under nitrogen. Removal ofthe solvent under reduced pressure afforded a white solid. The solid wastriturated with diethyl ether (200 mL), and the dicyclohexylthiourea wasremoved by filtration. The filtrate was evaporated, and acetonitrile(100 mL) was added to the resulting residue. The remaining dicyclohexylthiourea was filtered, and the filtrate was evaporated under vacuum toafford an oil. Flash chromatography on silica gel using CH₂ Cl₂ 50:hexane 50: Et₃ N 1 gave 4.31 g of2-[N-(5-bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)] aminoethylisothiocyanate as a white solid. Recrystallization from diethylether/hexane gave an analytical sample.

mp 83-85° C. ¹ H NMR (90 MHz CDCl₃) δ 3.84 (m, 4 H), 4.69 (s, 2 H,ArCH₂), 6.33 (d, J=8.3 Hz, 1 H, pyridine H-3), 7.40 (m, 4 H), 8.20 (d,J=2 Hz, 1 H, pyridine H-6). ¹³ C NMR (90 MHz CDCl₃) δ 43.34, 49.19,52.71, 107.70, 108.19, 125.74, 128.34, 130.83, 140.10, 148.71, 155.65.Anal. Calcd for C₁₅ H₁₂ BrCl₂ N₃ S: C, 47.01; H, 3.16; N, 14.62. Found:C, 46.93; H, 3.32; N, 14.56.

A suspension of 4-(4(5)-imidazolyl)piperidine dihydrochloride (387 mg,1.73 mmol) and triethylamine (350 mg, 3.50 mmol) in THF (30 mL) wasstirred for 2 h at room temperature under nitrogen and treated dropwisewith 2-[N-(5-bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)] aminoethylisothiocyanate (662 mg, 1.73 mmol) in THF (15 mL). After stirringovernight, considerable starting material remained. The reaction mixturewas heated at 60° C. for 24 h, cooled to room temperature, filtered, andevaporated to yield an oil. Flash chromatography on silica gel using asolvent system of EtOAc 85: CH₃ OH 15: concentrated NH₄ OH 1 afforded700 mg of the title compound as a white foam.

¹³ C NMR (CDCl₃) δ 31.42, 34.78, 46.31, 47.67, 47.89, 51.46, 107.59,108.40, 113.76, 125.79, 128.28, 130.93, 131.42, 133.05, 134.67, 137.38,140.47, 142.09, 147.84, 157.26, 180.99. Anal. Calcd for C₂₃ H₂₅ BrCl₂ N₆S: C, 48.61; H, 4.42; N, 14.79. Found: C, 49.09; H, 4.76; N, 14.54.

EXAMPLE 2

1-(3H-Benzotriazol-5-yl)-3-(2-((5-bromopyridin-2-yl)-(3,4-dichlorobenzyl)amino)-ethyl)thiourea##STR19##

A solution of 5-aminobenzotriazole (312 mg, 2.28 mmol) in THF (40 mL)was stirred under nitrogen and treated with a solution of2-[N-(5-bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)] aminoethylisothiocyanate (950 mg, 2.28 mmol) in THF (25 mL). After stirringovernight, a TLC (silica gel, EtOAc 9: CH₃ OH 1: concentrated NH₄ OH0.5) of the reaction mixture indicated that only starting material waspresent. The reaction mixture was refluxed for 48 h, cooled to roomtemperature, and evaporated under reduced pressure to afford a brownfoam. Trituration of the foam with hexane afforded a solid which wasrecrystallized from ethyl acetatehexane to give 1.08 g of the titlecompound:

mp 189.5-191.5° C.; ¹ H NMR (DMSO-d₆) δ 3.67 (m, 4 H), 4.78 (s, 2 H,ArCH₂), 6.78-8.06 (m, 11 H), 9.86 (s, 1 H, N═N--NH); ¹³ C NMR (DMSO-d₆)δ 46.84, 50.01, 106.02, 108.08, 115.99, 122.92, 127.04, 128.67, 129.21,130.56, 131.00, 136.47, 139.94, 147.63, 156.24, 180.72. Anal. Calcd forC₂₁ H₁₉ BrCl₂ N₇ S: C, 45.67; H, 3.47; N, 17.75. Found: C, 45.94; H,3.40; N, 17.87

EXAMPLE 3

1-(2-((5-Bromopyridin-2-yl)-(3,4-dichlorobenzyl)amino)ethyl)-3-(4-piperidine-1-ylphenyl)thiourea##STR20##

A solution of N-(4-aminophenyl)piperidine (388 mg, 2.16 mmol) in THF (40mL) was stirred under nitrogen and treated dropwise with2-[N-(5-bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)] aminoethylisothiocyanate (0.90 g, 2.16 mmol) in THF (15 mL). The reaction mixturewas stirred at 40° C. for an additional 24 h. Evaporation of the solventafforded a dark brown oil. Trituration with hexane gave a solid whichwas recrystallized from diethyl ether-hexane to yield 930 mg of a thetitle compound:

mp 146-147.5° C.; ¹ H NMR (CDCl₃) d 1.66 (m, 6 H), 3.21 (m, 4 H), 3.80(br s, 4 H), 4.85 (s, 2 H, ArCH2), 6.32 (d, 1 H, pyridine H-3), 7.30 (m,11 H, ArH and NHC═SNH); ¹³ C NMR (CDCl₃) d 24.16, 25.67, 45.07, 47.07,49.84, 51.30, 107.59, 116.52, 125.73, 127.36, 128.23, 130.83, 137.60,140.04, 148.11, 151.36, 156.56, 181.37. Anal. Calcd for C₂₆ H₂₈ BrCl₂ N₅S: C, 52.62; H, 4.76; N, 11.80. Found: C, 52.61; H, 4.69; N, 11.78.

EXAMPLE 4

1-(2-((5-Bromopyridin-2-yl)-(3,4-dichlorobenzyl)amino)propyl)-3-(4-piperdine-1-ylphenyl)thiourea##STR21##

The title compound was prepared analogously to example 3 with2-[N-(5-bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)]aminopropylisothiocyanate instead of with2-[N-(5-bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)]aminoethylisothiocyanate.

mp 125-127° C.; 1H NMR (CDCl₃) δ 61.69 (m, 8 H), 3.22 (m, 4 H), 3.63 (m,4 H), 4.49 (s, 2 H, ArCH2), 6.15 (d, 9 Hz, 1 H, pyridine H-3), 6.90-7.56(m, 11 H). Anal. Calcd. For C₂₇ H₃₀ BrCl₂ N₅ S: C, 53.39; H, 4.98; N,11.53. Found: C,53.29; H, 4.99; N, 11.16.

EXAMPLE 5

1-(2-((5-Bromopyridin-2-yl)-(3,4-dichlorobenzyl)amino)butyl)-3-(3-(1H-imidazol-4-yl)phenyl)thiourea##STR22##

The title compound was prepared analogously to example 3 with2-[N-(5-bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)]aminobutylisothiocyanate instead of with2-[N-(5-bromopyrid-2-yl)-N-(3,4-dichlorobenzyl)]aminoethylisothiocyanate and 4-(3-aminophenyl)-1H-imidazole instead ofN-(4-aminophenyl)piperidine.

mp 140-160° C.; ¹ H NMR (CDCl₃) δ 1.49 (m, 4 H), 3.47 (m, 4 H), 4.51 (s,2 H, ArCH2), 6.22 (d, 1 H, pyridine H-3), 7.30 (m, 10 H), 8.00 (d, 1 H,pyridine H-6), 8.53 (br s, 1 H, imidazole N--H); ¹³ C NMR (CDCl₃) δ24.43, 26.38, 44.85, 48.48, 50.92, 106.67, 107.32, 121.51, 123.41,126.17, 126.61, 128.61, 130.18, 130.56, 130.88, 132.56, 135.11, 135.97,137.11, 138.79, 148.43, 156.18, 180.56.

EXAMPLE 6

N1-[3-[N-(4-Bromo-benzyl)-N-(pyridin-2-yl)amino]propyl]-4-(pyridin-2-yl)piperazine-1-carboxamidine trihydrochloride##STR23##

To a solution of propane-1,3-diamine (310 ml, 3.63 mol) in dry pyridine(75 ml) kept under an atmosphere of nitrogen 2-bromo-pyridine (70 ml,0.73 mol) was added . The reaction mixture was heated at reflux for 18h, cooled and the volatiles evaporated in vacuo. To the residue wasadded tetrahydrofuran (1000 ml) and the precipitate was filtered off andwashed with tetrahydrofuran (500 ml). The solvent was evaporated invacuo and the residue purified by distillation at 95-97° C. and 2·10⁻²mbar affording 83.37 g of N1-(pyridin-2-yl)propyl-1,3-diamine.

¹ H NMR (200 MHz, DMSO-d₆) δ_(H) 1.20 (bs, 2H, NH₂), 1.74 (p, 2H), 2.82(t, 2H), 3.34 (q, 2H, CH₂ --NH), 4.86 (bs, 1H, NH), 6.35 (dt, 1H), 6.51(ddd, 1H), 7.37 (ddd, 1H), 8.04 (ddd, 1H).

To a mixture of sodium hydride (5.86 g, 60% dispersion in mineral oil,0.1415 mol) in dry dimethylsulfoxide (250 ml) was slowly added asolution of N1-(pyridin-2-yl)propane-1,3-diamine (20 g, 0.1323 mol) indry dimethylsulfoxide (50 ml) at room temperature under an atmosphere ofnitrogen. The reaction mixture was stirred until gas evolution hadexceed. A solution of 4-bromobenzyl bromide (36.09 g, 0.1415 mol) in drydimethylsulfoxide (100 ml) was slowly added at room temperature. Thereaction mixture was stirred for 48 h at room temperature. The reactionmixture was poured onto ice water (500 ml) and extracted with ethylacetate (3×250 ml). The combined organic extracts were washed with water(3×150 ml), dried (MgSO4), filtered and concentrated in vacuo. Theresidue (40.56 g) was washed with n-heptane (30 ml) which afforded 36.77g of crude N-1-(4-bromobenzyl)-N-1-(pyridin-2-yl)propane-1,3-diamine.The crude product (20 g) was purified by column chromatography on silicagel (900 ml) using dichloromethane/methanol/triethylamine 9:0.5:0.5 aseluent affording 13.75 g ofN1-(4-bromobenzyl)-N1-(pyridin-2-yl)-propane-1,3-diamine as an oil.

¹ H NMR (200 MHz, CDCl₃) δ_(H) 1.64 (s, 2H, NH₂), 1.74 (t, 2H), 2.72 (t,2H), 3.60 (t, 2H, CH₂ --N), 4.67 (s, 2H, CH₂ -Ph), 6.41 (d, 1H), 6.53(dd, 1H), 7.07 (d, 2H), 7.33-7.41 (m, 3H, 8.13 (dt, 1H).

To a mixture of 1-(2-pyridyl)piperazine (10 ml, 64.37 mmol) indichloromethane (200 ml) was added N-benzoyidimethyldithioimidocarbonate(14.64 g, 65.01 mmol) and the reaction mixture was stirred for 18 h atroom temperature. The volatiles were evaporated in vacuo and the residuecrystallised from a mixture of heptane/diethyl ether 9:1. The solid wasfiltered off, washed with a mixture of heptaneldiethyl ether 1:1 anddried in vacuo affording 20.86 g ofN-[methylsulfanyl-(4-(pyridin-2-yl)piperazin-1-yl)methylene]-benzamideas a solid.

To a mixture ofN-[methylsulfanyl-(4-(pyridin-2-yl)piperazin-1-yl)methylene]-benzamide(2.9 g, 8.52 mmol) in pyridine (50 ml) was addedN1-(4-bromobenzyl)-N1-(pyridin-2-yl)-propane-1,3-diamine (3 g, 9.37mmol) and the reaction mixture was heated at reflux for 18 h. Thevolatiles were evaporated in vacuo and the residue dissolved indichloromethane (100 ml) and evaporated in vacuo. The residue waspurified by column chromatography on silica gel (600 ml) using first amixture of ethyl acetate/triethylamine 95:5 (1 l) followed by a mixtureof ethyl acetate/methanol/triethylamine 90:5:5 as eluents affording 2.95g ofN-[[3-[N-(4-bromo-benzyl)-N-(pyridin-2-yl)amino]propylamino]-(4-pyridin-2-yl-piperazin-1-yl)methylene]benzamide as a foam.

N-[[3-[N-(4-bromo-benzyl)-N-(pyridin-2-yl)amino]propylamino]-(4-(pyridin-2-yl)piperazin-1-methylene]benzamide(0.5g, 0.816 mmol) was dissolved in 1.5 N hydrochloric acid (10 ml) andheated at 100° C. for 21 h in a screw cap ampoule. The cooled reactionmixture was washed with diethyl ether (3×10 ml) and evaporated in vacuoaffording a residue which was dissolved in ethanol (20 ml) andevaporated in vacuo the later repeated three times affording 496 mg ofcrude product as a foam. The crude product (496 mg) was suspended in 30%sodium methoxide in methanol (0.51 ml) and stirred at room temperaturefor 10 min. To the reaction mixture was added a solution ofdi-tert-butyl dicarbonate (361 mg, 1.61 mmol) in dioxane (25 ml) and theresulting mixture was stirred for 18 h at room temperature. The reactionmixture was filtered and the volatiles were evaporated in vacuoaffording 611 mg of a syrup which was purified by column chromatographyon silica gel (180 ml) using first a mixture of ethyl acetate/methanol90:10 as eluent affording 215 mg of[[3-[N-(4-Bromobenzyl)-N-(pyridin-2-yl)amino]propylamino]-(4-(pyridin-2-yl)piperazin-1-yl)methylene]carbamicacid tert-butyl ester as foam. To a mixture of the tert-butyl ester (215mg, 0.353 mmol) in ethyl acetate (15 ml) was added 1N hydrochloric acidin diethyl ether (1.8 ml, 1.77 mmol) and the reaction mixture wasstirred for 61 h at room temperature. The reaction mixture wasevaporated in vacuo and to the residue dissolved in methanol (10 ml) wasadded 1N hydrochloric acid in diethyl ether (22 ml, 1.77 mmol). Theresulting mixture was stirred for 60 h at room temperature. The reactionmixture was evaporated in vacuo and the residue was dissolved in ethanol(15 ml) and evaporated in vacuo affording 194 mg of the title compoundas a foam.

¹ H NMR (400 MHz, D₃ COD) δ_(H) 2.12 (m, 2H), 3.46 (t, 2H), 3.84 (m,6H), 3.93 (m, 4H), 4.96 (s, 2H, CH₂ -Ph), 7.05 (m, 2H), 7.26 (m, 3H),7.39 (d, 1H), 7.55 (d, 2H), 8.00-8.12 (m, 4H).

We claim:
 1. A compound of formula I: ##STR24## wherein A is pyridinylor phenyl optionally substituted with one or more halogens, aminogroups, hydroxyl groups, nitro groups, C₁₋₆ -alkyl groups or C₁₋₆-alkoxy groups;B is phenyl, pyridinyl or naphthyl optionally substitutedwith one or more halogens, amino groups, hydroxyl groups, C₁₋₆ -alkylgroups or C₁₋₆ -alkoxy groups; m is 0, 1, 2, 3, 4, 5or 6; n is 0, 1, 2or 3; Y is a valence bond or a group having the formula ##STR25##wherein q and s each independently are 0, 1, 2, 3, 4 or 5 and q+s is 1,2, 3, 4 or 5; R¹ is hydrogen or C₁₋₆ -alkyl optionally substituted withhalogen, amino, hydroxy or alkoxy; X is ═S, ═O or ═NR³, wherein R³ ishydrogen, --C(O)Ph, or --CN; E is a group having the formula ##STR26##wherein D is aryl, optionally substitute with one or more halogens,amino groups, hydroxyl groups, C₁₋₆ -alkyl groups, C₁₋₆ -alkoxy groups,or aryl groups; R² is hydrogen or C₁₋₆ -alkyl optionally substitutedwith halogen, amino, hydroxy, alkoxy or aryl, with the proviso that ifm=0 then Y is not a valence bond; or a pharmaceutically acceptable saltthereof.
 2. The compound of claim 1 wherein A is pyridinyl.
 3. Thecompound of claim 1 wherein B is phenyl.
 4. The compound of claim 1wherein B is naphthyl.
 5. The compound of claim 1 wherein m is 0, 1, 2,3 or
 4. 6. The compound of claim 1 wherein n is
 1. 7. The compound ofclaim 1 wherein X is ═S, ═NH or ═NC(O)Ph.
 8. The compound or claim 1wherein q+s is
 4. 9. The compound of claim 1 wherein X is ═S, ═NH or═NC(O)Ph.
 10. The compound of claim 1 wherein D is phenyl,benzotriazolyl, imidazolyl or pyridinyl, optionally substituted with oneor two halogens, amino groups, hydroxyl groups, C₁₋₆ -alkyl groups, C₁₋₆-alkoxy groups, piperidinyl groups or aryl groups.
 11. The compound ofclaim 1 wherein D is phenyl substituted with an imidazolyl group or isimidazolyl, optionally substituted with one or two halogens, aminogroups, hydroxyl groups, C₁₋₆ -alkyl groups, C₁₋₆ -alkoxy groups,piperidinyl groups or aryl groups.
 12. The compound of claim 1 wherein Dis (4-piperidine-1-yl)phenyl.
 13. The compound of claim 1 wherein D is(1H-Imidazol-4-yl)phenyl.
 14. The compound of claim 1 wherein D is3H-benzotriazol-5-yl.
 15. The compound of claim 1 whichis:1-(2-((5-Bromopyridin-2-yl)-(3,4-dichlorobenzyl)amino)ethyl)-3-(4-piperidine-1-ylphenyl)thiourea;1-(3H-Benzotriazol-5-yl)-3-(2-((5-bromopyridin-2-yl)-(3,4-dichlorobenzyl)amino)ethyl)thiourea;1-(2-((5-Bromopyridin-2-yl)-(3,4-dichlorobenzyl)amino)propyl)-3-(4-piperidine-1-yl-phenyl)thiourea;1-(2-((5-Bromopyridin-2-yl)-(3,4-dichlorobenzyl)amino)butyl)-3-(3-(1H-imidazol-4-yl)phenyl)-thiourea;1-(3-(((5-Bromopyridin-2-yl)-(3,4-dichlorobenzyl)amino)methyl)cyclohel)-3-(3-(1H-imidazol-4-yl)phenyl)thiourea;ora pharmaceutically acceptable salt thereof.
 16. A pharmaceuticalcomposition comprising a compound of claim 1 together with apharmaceutically acceptable carrier or diluent.
 17. The pharmaceuticalcomposition of claim 16 in unit dosage form, comprising from about 10 toabout 200 mg of the compound.
 18. A method for treatment of type Idiabetes, type II diabetes, CFS, endocrine tumors, exocrine tumors,dwarfism, acromegaly, other growth abnormalities, autoimmune diseases,rheumatoid arthritis, Alzheimer's disease, pain, anxiety, memorydisorders, affective disorders, intestinal water congestion, diarrhea,restenosis, arteriosclerosis, asthma, mucoviscidosis, obesity, ulcer,acute pancreatitis, a disease associated with an adverse condition inthe retina and/or iris-ciliary body, comprising administering to asubject in need thereof an effective amount of a compound of claim 1.19. The method of claim 18 wherein the amount is in the range of fromabout 0.0001 to about 100 mg/kg body weight per day.
 20. The method ofclaim 18 wherein the amount is in the range of from about 0.001 to about50 mg/kg body weight per day.